Telephone system.



. Nn. 691,28l. Patented Ian. 14; 1902.-

v F. E. MAYBEBRY. TELEPHUNE SYSTEM.

I {Application filed Mar. 18, 1901.) (No Model.) 4 Sheets-Sheet I.

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F. E. MAYBERBY. TELEPHQNE SYSTEM.

A lication filed mm m, 1901.

(No Model.) 4 Sheets-Shut 2.

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F. E. 'MAYBERRY.

TELEPHONE SYSTEM.

(Application filed Mar. 18, 1901.) (No Mqdel.) 4 Sheets-Sheet a.

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U ITED; STATES PATENT OFFICE.

FRANK E. MAYBERRY, OF ll/IEDFORD, MASSACHUSETTS, ASSIGN'OR, BY DIRECT AND MESNE ASSIGNMENTS, OF FIVE-EIGHTHS TO WATSON M. HOLMES, OF I-IOOSICK FALLS, NEW YORK, AND GEORGE A. LOWRY,

or oiuoAco, ILLINOIS.

SPECIFICATION forming part of Letters Patent No. 691,281 dated January 14, 1902.

Application filed March l8 19Ql. Serial No. 51,668. (No model.)

To ctZZ whom, iv may concern:

Be it known that I, FRANK E. MAYBERRY,

of Mediord, county of Middlesex, and State.

of Massachusetts, have invented an Improvement in Telephone Systems, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

The present invention relates to a tlephone signaling system and is embodied in a selective signaling system for party-lines or lines each of which contains two or more stations, the object of the invention being so to arrange the signaling devices that the central oflice can be called from any station on a line Without producing a signal at any other station on the same line, while a call from the central oflice will affect the signaling device at one station only on the line, so that no one of the subscribers who is not wanted will be disturbed.

The iuventionfurther relates to means for looking out the telephone instruments at all the stations on a line except the one which has been called or is calling, so that the line can be controlled for one station Without interference caused by the attempt of another subscriber on the same line to call up the central ofliee.

The invention is embodied in a system in which the signal-controlling and telephonecontrolling devices are independent of the signaling devices and telephones, but are adapted to selectively control the same, the ordinary line-circuit conductors, however, being used as part of the signal-controlling circuit. Each signal-controlling device has a special circuit at each instrument and the several circuits are in multiple, so that any number of stations on a line can" be equipped.

The controlling devices for the signalingcircuit and the telephone-circuit at each instrument are operated by an electromagnetic system included in the signal-controlling circuit at each station, the said system including a polarized armature or armatures, so that impulses of current in one direction will operate to set the several signal-controlling devices in an abnormal position, While an impulse of current in the opposite direction will operate to restore all of the signal-controllin g devices to normal. The several controlling devices on a single line are arranged to operate in unison and are so related to each other that a certain number of movements participated in by the controlling devices will place thesignaling device at one station in condition to receive a signal and the signaling devices at the other stations on the same line in such condition that no signal can be received, the same operation placing the telephone at the selectedstation in condition for use and the telephones at the other stations in such condition that they cannot be connected with the line.

In applying the invention, for example, to the ordinary telephone system the signalcontrolling device is provided with a circuitcloser adapted when the said device is properly operated to close the signaling-circuit at the selected station, the signaling-circuits at the other stations being left open, so that when the usual signaling-current is switched onto the line from central ofiice it will affect the signal at the selected station only. The same devicewhich operates the traveling circuit-closer may be arranged to prevent the telephone-circuit from being closed, as by means of a mechanical locking device cooperating, for example, with the gravity-hook at each station and preventing the same from rising when the receiver is removed, so that the telephone cannot be connected with the line. In this construction the signal-receiving circuit or bell-circuit at every instrument is open when the parts are in normal position, (so that no signal will be received when a subscriber on the same line calls central,) and in order that a subscriber may be enabled to call central each instrument is provided with a manually-operating device adapted to close the signal-sending circuit and at the same time to leave the telephone-locking device in such condition that the receiver and trans mitter circuits can be closed. This may be accomplished in various ways, a simple and practical way of doing it consisting in dividing the signaling-circuit-into branches, one of which contains the magneto or other signal-sending device andhas a break which is normally closed by a circuit-closer cooperating with the traveling member of the controlling device and a normally open break adapted to be closed by a push-button, such ,Will prevent the sending of a signal after the signal-controlling device has begun to operate, the signal-sending circuit in this case being entirely independent of the signal-receiving circuit, as is common in this system.

A further feature of the invention is embodied in means for automatically sending a single impulse from the special battery over the calling-line in response to the impulse which gives the signal at the central office. This is accompanied by means for preventing the impulse of current from affecting the circuits .at the calling-station, so that while the calling subscriber can be properly connected with the line every other subscriber on the same line is locked out without the intervention of the operator at the central office. This renders it unnecessary for the operater to send locking impulses over the calling-line, and the pole-changing switch may advantageously be arranged so that signalsetting impulses will be sent only over the called line, both lines, however, being included in circuit when the switch is reversed to send the restoring impulse.

The invention further relates to certain novel details of construction and arrangement,which will be hereinafter more fully described.

Figure 1 is a diagram view showingfour stations on a line and indicating the special source of current which is used to operate the signal'controlling devices, the other centraloffice connections being omitted. Fig. 2 is a diagram showing one cord-circuit at central office to indicate the manner in which the special source of current may be connected with the line and alsothe connection with the usual source of alternating currents for.

trolling devices may be connected with existing instruments without interfering with the regular circuits.

Referring to Fig. 1, each signaling device of a series located, respectively, at different stations on the same line is provided with a circuit-controllerhaving terminals a a in the all of them are arranged to be moved in uni= son-a certain distance in response to a single impulse of current sent over the line from a special source of current at the central office,

such as the battery A. The circuits forthe battery-current at each. station (whether grounded or bridged across the line) are entirely independent of the ordinary signalingcircuits and the telephone-circuits and are arranged in multiple with each other, whereby the currents sent out from the battery A will be divided among all the instruments on a given line, so that the number of instrumen ts to which the devices embodying the invention can be applied is practically unlimited.

The traveling members a when standing in their normal positions are set at different distances from the circuit-closers a and o at the different stations, that at one station, for example, requiring two movements to bring it into engagement with the contact-pieces, that at another station requiring three movements, and so on, there being, however, at least two movements required to complete the circuit at any station, the first movement, as will be hereinafter described, being for the purpose of looking out the several stations on the line.

In the drawings the several devices are shown in the positions in which they will be if four impulses of current have been sent over the line to call up station No. 3. It will be seen that at stations Nos. 1 and 2 the traveling member a has gone beyond the contact-pieces a and a while at station No. at it has not reached the said contact-pieces, so

that the signaling-circuit is closed at station 3 only. It, therefore, a current is sent out over the line from the source commonly used for signaling-for example, the magneto B, Fig. 2it will affect only the bell B at station No. 3, since the bell-circuits at all the other stations are open at the contacts a a In conjunction with the signal-controlling device proper each station is provided with a telephone-controlling device or means for preventing the telephone from being used at any station except the one which has been selected and the station originating the call.

As herein shown, the said telephone-com with a notch b on its periphery, the said periphery being so situated as to engage a projection G which is connected withthe gravity-hook in such a way as to prevent the same from rising except when the said projection is in line with the said notch. The said disk may also be utilized to carry the contactpiece a above described, and the relative positions of the said contact-piece a and notch b are such that when the contact-piece a stands in position to bridge or connect the terminals a and a the notch will be in position to permit the hook O to rise. As has been stated, however, when the device is in its normal position the contact-piece 0. is in a position to leave the contact a and a open, and consequently the notch 17 is not in a position to permit the hook to rise and close the telephone-circuit. In order, therefore, that a calling subscriber may be able to use his telephone, each instrument is provided with means whereby the signal-sending circuit may be completed and the telephone-circuit also completed at the will of the subscriber, assuming that no other station on his line is busy. This may be accomplished in various ways, it being essential only that the'suoscriber should be provided with means for manually closing the signaling-circuit at his own station and with means whereby the gravity-hook may be free to move to the position to close thetelephone-circuit if the station has not been previously locked out.

As herein shown, each locking-disk bis provided with a supplemental notch b, which normally stands in such position as to permit the rising of the gravity-hook, it being obvious, however, that the said gravity-hook cannot rise when the disk is in any position other than its normal position or its selected position. The signal-sending circuit, which in cludes the magneto, is provided with two breaks, one including the terminals 0 c ,which are normally bridged or connected by a contact member 0 (shown in normal position in Fig. 6,) also carried by the disk b, and the other having the terminals d d adapted to be closed by a manual operating device, such as a push-button (1 When the instruments are in their normal condition, therefore, the subscriber by pressing the push-button can complete a signaling-circuit and open communication with central office. If, however,

the controlling device has been previously.

phone in condition for use.

called subscriber may actuate the clearingout signal. Y

The movements of the signal-controlling and telephone-controlling devices above described are produced by the movement of armatures under the control of an electromagnetic system located in a special circuit at each station and adapted to receive current from a special independent source at the central office, as the battery. The system is so arranged that impulses of current sent from the said battery A over the several signalcontrolling device circuits, which are arranged in multiple along the line, will produce step-by-step movements of the several signalrcontrolling devices, each station requirin g a number of impulses peculiar to itself to close its signaling-circuit and place the tele- This is accomplished by providing each instrument with two armatures, one of which will respond to a current flowing in one direction, this being connected with a device for stepping up or setting the several signal-controlling devices, and the other of which will respond only to currents which flow in the opposite direction, the said last-named armature cooperating with a device for restoring all the controllers to normal condition. This may be accomplished by polarizing one or both armatures, it being essential, however, to use only one polarized armature, as will be hereinafter described. I

A practical mechanical construction is illustrated in Figs. 3, 4, and 5, the said construction including the electromagnets e and f, the

former of which will be referred to as the stepping-up electromagnet and the latter as the restoring electromagnet. The electromagnet e is provided with the armature e pivoted at e and having connected therewith a pawl 6 shown as pivoted at 6 upon the arm e, to which the said armature is connected, the said pawl having a spring e adapted to hold the armature normally retracted. The said armature is arranged to respond only to impulses of current in one direction, and the pawl is adapted to act upon a ratchet-wheel b mounted on the shaft 12 the teeth being cut so that each movement of the said armature when attracted will move the said wheel one 'notch. The shaft 19 is also provided with a restoring-spring N, Fig. at, against the stress of which it is rotated by the pawl 6 and at the end of each step the restoring movement is prevented by the action ofapawl,which is connected with the armature f of the restoringmagnet f. The said armature f is shown as permanently polarized by the permanent magnet f to which it is connected, the polarity being such that it will not respond to impulses of current which are sent in proper direction to step up or set the controlling device. The said armature f is shown as connected with the pawl which is pivotally supported and acted upon by a restoring-spring f shown as connected with a member f carried by the armature 2 the said member '.bein' interposed for a purpose to be hereinafter described. The pawl f therefore acts in c011- junction with the ratchet-wheel b as a stop to hold the shaft 1) at the end of each stepcircuits is shown in its simplest form in Fig.

1, in which the only central-office connection illustrated is that of the special battery A, which is provided with a pole-changingswitch A which is shown conventionally in this figure-and more in detail in Fig. 2,in connection .with which it will be hereinafter fully described. Assuming, for example, that the positive pole of the battery is connected with line-wire 1, an impulse of current is sent from terminal 10 at each station over wire 11 to the gravity-hook C and thence through wire 12 to the stepping-up magnet e, from said magnet through wire 13 to the magnetf, through said magnetfto the wire 14, and thence through wire 15 to the terminal 20 and back through line 2 to the negative'side of the battery. Assuming the armature f to be so polarized as not to respond to the current in this direction, it is obvious that the armature e alone will be attracted and that the device'at each station may be stepped up as many notches as there'are impulses of current sent over the line.

The pole-changing switch is normally at an intermediate position, with the battery A disconnected t'rom the line, and as soon as it has been moved a proper number of times it is left standing in normal position, the operator then switching in the signaling-current from the source B by means of the switch or tablekey B Fig. 2, in the ordinary way, the battery A being disconnected until conversation is finished and it is necessary to restore the controlling devices to normal. Upon receivin g the clearing-out signal the operator at central oftice moves the pole-changer in the opposite direction, connecting the positive terminal'of the battery A with the line'2 and the negative terminal with the line'1,the circuit at each station then being from terminal 20 through conductor 15, conductor 14, re

storing-magnet f, conductor 13, stepping-up magnet e, conductor 12, gravity-hook C, conductor 11, to terminal 10. The current, however, fiowing through both magnetsin series and in a direction to attract the polarized armature f will attract the said armature at once and in so doing will close a switch comprising the terminals f and f thus connecting the wire 13 With the wire 12 and through the gravity-hook G to wire 11 and short-circuiting the stepping-up magnet e, this taking place so quickly that the armature e is not attracted for a length of time sui'licient to cause the pawl e to prevent the return move 'ment of the ratchet-wheel b, which is then released by the pawl f The said pawl e, as shown, is normally out of engagement with the ratchet-wheel b and consequently only acts on said wheel when the armature c is attracted.

In the description of the signal-controlling device reference has thus far been mainly madeto Fig. 1, where part of the circuits are omitted for the sake of clearness. In Fig. 6, on the other hand, all of the circuits are included and the several mechanical parts of the actual instrument are shown disconnected in order that the circuits may be clearly traced from one to another, the purpose being mainly to indicate how an ordinary walltelephoue may be wired when the controlling device embodying the invention is applied thereto without materially changing the original wiring. Referring to said Fig. 6, the several circuits may be traced as follows: The circuit for the impulses of current used in setting the devices is as follows: wire 11, (which is connected with line-wire 1,) gravity-hook 0, wire 12, binding -post 120, wire 121, (from upper part of hinding-post,) magnet 2, wire 13, magnet f, (the polarized armature 0t which is not aiiected by current flowing in this direction,) wire 14 to the point G, where said wire 14: is connected with the return-Wire 15, the said return-Wire completing the circuit to the binding-post or terminal 20, and thence to line-Wire 2. The circuit for the restoring-current starting with terminal 20 passes through wire 15, point G, wire 14,'electromagnetf, (in the right direction to attract the armature thereof,) wire 13, electromagnet (2, wire 121, binding-post120, wire l2,gravityhook O, and wire 11, thiscircuit, as above explained, being for the'first impulse only, the magnet e being short circuited through the wire 13 as soon as the armature f is attracted, as indicated in dotted lines. The contact-pieces f (at the end of wire 13") and f are then connected, f being connected with wire 121 at binding-post 120. The signal-sending current starting with the fieldterminal of the magnetoNpasses through the wire 15, binding-post 120, Wire 12, gravityhook C to the line through wire 11, (a portion of the current being shunted over the bellcircuit, which will be hereinafter traced, and the magnets e and f,) thence through the drop at central office and returning to the other terminal of 'the magneto N through the terminal 20, the wire 15, the switch member d switch member d, (the push-button d being in the dotted-line positiom) wire 15, the contacts 0 and c of the normally closed switch, and the wire 15. This circuit is also in multiple with the circuits containing the controlling-device electromagnets. and the bell-magnets. The bell-circuit for signals from central office passes through thewire 11, gravity-hook 0, wire 12, binding-post 120, wire 12 to the bell-magnet coils, thence ductor 16 to conductor 12.

through wire 12 to binding-post 12, wire 12 to the member 0 of the normally closed switch, (the said switch, however, being open when a signal is coming-in on account of the previous movement of the controlling-device,) wire 12 to the members a and a of the normally open switch, (which have been previously bridged by the operation of the controlling device from central office,) from member a to wire 12 contact G, wire 15 to terlow resistance would be afforded for the step ping-up impulses of current through his own telephone circuit, which would practically shunt the higher-resistance electromagnets along the line,upon which magnets the stepping-up operation depends. To obviate this diiiiculty, a special normally open circuit may be employed, starting from a point between the gravity-hook contact and the inductioncoil and terminating at .the wire 12, the said circuit having terminals adapted to be bridged by a contact member (1, connected with the switch-member 01 but being insulated from it, the said circuit being herein shown as consisting of the conductor 16, contact-point 16, contact point 16,'(which contacts are adapted to'be bridged by contact member (1 con- The receiver-circuit is normally closed through a back contact 16 through switch member d and wire 15, so that after the receiver hasbeen lifted ifthe push-button (l is pressedin the receiver will be cut out of the circuit at 1-6 and theelectromagnets e andfand the bell-magnetiucluded in the circuit in multiple atfording the proper amount of resistance to distribute the current th'roughout'the line.

'The receiver having been removed, the con- I trolling device at the station will be locked by the projection 0 so that the calling instrument cannot be affected by the impulses of current passing through the electromag, nets e andf. When the bell at the calling in- "strument rings, it.will indicate that the called instrument has been stepped into cir- As best shown in Fig. 5, the instruinent'can be contained in a comparatively small box or casing which may be secured to the bottom of the magneto-box, the member 0 in this case being directly formed upon a supplemental arm 0 pivoted at (J in the casing, and connected with the gravity-hookO by means ofa rod or link C if desired, moreover, the device can be provided with a visual signal, which will appear when the line is busy, the said signal being herein shown as an arm D,

having a projection D with the word Busy printed on it, the said word being normally 'hiddenbehind the front of the casing, but

adapted to appear through an opening D (dotted lines) when the controlling device has been moved.

As herein shown,the arm D is loosely mounted on the shaft 12 and is provided with a weight D which tends to cause the said arm to tip toward the position shown in Fig. 3. The said arm is normallyheld in the position shown in Fig. 5, however,by means of a stop D on the disk (2, which stop supports the arm, as shown,

when the disk is in normal position. As soon, however, as the disk is rotated in the direction to step up the controlling'device the stop D will move away from the arm D,which will then drop and be arrested by a stop D in the casing, the position then being such-that the word-Busy will show. When the disk is restored to normal, the stop D will carry the arm D back to the position shown in Fig. 5 and support it in such'position.

In order to prevent possible interference which might'occur duringthe interval of time between the signaling of the central office by a subscriber and the manipulation by the operator at centraloliic'e of the signal-controlling mechanism, it is desirable o provide means for ai'itomatically looking out all instruments on a calling-line in response to the act of any subscriber on the said line in sending in a signal to central oflice. As a practical means 'for accomplishing this purpose the signal-drops h, Fig. 2, of the several lines may be arranged to close a circuit fromthe special battery A out over the calling-line, the said circuit being broken by the insertion of the answering-plug into the answering-jack. Assuming that a subscriber on the line F, Fig. 2, has sent in a signal energizing electromagnet 72, and causing the drop it to fall, the said drop it will bridge a pair of contacts 30 and 31 connectin g together the wires 30 and 31., the former being connected with the line-wire 1 and the latter with the positive pole of the battery A,assuming that the stepping-up current goes from the positive pole to the terminal 10, as described in conjunction with Fig. l. The negative pole of the battery is connected through the wires 31 31 31 with a contact-piece31",

"which is normally in contact with line-wire 2, but adapted to be carried out of contact therewith when the answering-plug is inserted. As soon, therefore, as any subscriber sends in a signal an impulse from the signalcontrolling battery will be sent over the line from which the signal comes, causing the signal-controlling devices on the said line to be stepped up one notch, which is sufficient to break all the signal-sending circuits and look all the telephones. To prevent the said impulse-from affecting the instrument from which the call is sent, the push-butt on d'-,which must be pressed in while the signal is being produced, is arranged to coact mechanically with the pawl e and hold the same out of engagement with the ratchet-wheel b duringthe attraction of the armature e at that station. The normal position of the parts is shown in dotted lines, Fig. 3, the push-button (Z having connected therewith a stop or projection (1 against which the pawl c normally'rests out of engagement with the ratchet-wheel, the said pawl, however, tending to slide upward from said projection toward the ratchet-teeth through the action of the spring (2 when the armature e is attracted. If the push-button d is pressed inward, however, (see dotted lines, Fig. 6,) it will prevent such .upward movement of the pawl until said pawl has passed the tooth with which it would naturally engage, so that it will not cause the ratchetwheel 6 to rotate. The calling instrument, therefore, is left in normal position,wh-ile the others are automatically locked in response to the signaling impulse. Since the stations on any calling-line are thus locked out in response to the-signaling impulse, it is not necessary or desirable to send any further im-- pulses over that line, but only over the line with which connection is desired. To this endv the polechanging switch and cordcir-, cuits are so arranged that the manipulation of theswitch to send stepping-up impulses connects the battery A only with the cords of the calling-plug, the reverse movement, however, connecting the cords of bothplu'gs-in order to restore the controlling devices on both of the connected lines...

As shown in Fig. 2, the pole-changing switch A has an operating member A ",provided with a handle A whereby it can be moved in either directiomsuch movement operating upon contacts A and A or A and A to connectthem, respectively, with the contacts A and A 01 A and A The operating'in embers A are mounted on a common shaft or rocker and both moved by the handle A being shown separate merely for the purpose of clearly indicatingthe circuits. The contacts A and, A are connected together by a wire andv through a wire 40 with the positive terminal of battery A. The contacts A and A are connected together by the wire 31 and through a wire with the wire 31, which leads to the negative side of the battery. The contacts A and A are connected together and both connected through the wire with the tip-wire ll of the callingplug H, and the contacts A and A are connected together and both connected with the sleeve-wire'I-l' of the calling-plug II. The corresponding wires J and J oftthe answering-plug J are connected, respectively, with terminals A and A, which arenormally in contact with the terminals A and A Assuming, therefore, the calling-plug II and the answeringplug J to be placed in such position that the wires H and J are respectively connected with the main wires 1 of connected lines and the wires J and H respectively, connected A will be connected, the contacts A and A will be connected, and the contacts A and A will be separated from the contacts A and A The circuitfrorn the battery A may then be traced as follows: Starting from the positive pole, current will flow through wires 31 and 40 to contact A thence through contact A to the sleeve-wire H, sleeve of the calling-plug H, line-wire 1, and back through line-wire 2, ti p'-wire H wire 60, contact-piece A, contact-piece A, wire 50, wire 31 to the negativepole of the battery. By separating the contacts A and A from thecontacts A and A the cord-wire J, which leads to the contact A is'disconnected from the cordwire H, and the cord-wire J which leads to contact A, is disconnected .from the cordwire H so that neither one of the cord-wires of the answering-plug is connected with the battery-terminals, andno'itnpulse is sent over the line whichoriginated, the call. To restore the controlling devic'es,.however, it is necessary to send an impulse ofcurrentin theoppositetdirection over both lines, which is accomplished by moving thehandle A to the right, thus'connecting terminal A with terminal A and terminal A with terminal A Terminals A and A are not by this movement, disconnected from terminals A and A, (which are permanently connected, respectively, with terminals A and A so that the cord -wires-J and 11 remain connected and the cord-wires J and H also remain connected. Thecircuit may be traced as follows: Starting from the negative pole of the battery A, the current passes through conductorv 31 condu'ctor'50, conductor 31 to contact member A contact member A ,wire

70 to cord-wire-Hg also dividingat the point A and passing lBllIOllglLCOl'llhlClTA and'contact A and wire SOto' cord-wire J thence out over both lines andback through cord,- wires H and J? to contactsAt and A join ing a't A and thence through contact A to contact A", wire 40, wire40, wire 31 to the positive pole of the battery. When the pole-.

changing switch is in itsnormal positiomas shown, and the answering-plug hasbeentery A has no connection. whatever with the line, and the cord-circuits are the same as usual, the wires H and J and H -and .1 being connected bythe' co'ntactmembers IA and A? and A and A, which are. then closed. The usual source ofsignaling-cur-rent B may 'then be switched onto the line through the calling-plug by means of the table-key B to callup the desired party, his instrument havingbeenpreviouslysteppedintocircuit. The clearing-out drop and the'listening-in key are indicated inthis drawing, but need no description, as they have nothing to do with this invention. p

his not intended to limit the invention to the specific construction hereinbefore shown and described, as modifications. may obviously be made without departing from the invention.

I claim- 1. In a signaling system, a device at each station for placing the instrument at said station in condition to receive signals; meaus'for operating said device by current flowing in one direction; a second device for placing the instrument at said station in such condition that no signal can be received; means for operating said second device by current flowing in the opposite direction; a source of current; and means for sending impulses of current from said source to said devices in either direction.

2. In a selective signaling system for a n u mber of stations, a device at each station for controlling the signaling instrument at said station; a multiple circuit for the several devices; a source of current; means for sending current from said source in either direction over said multiple circuit; means whereby current flowing in one direction will place one of the devices in condition to receive signals; and means whereby current flowing in the other direction will place all of the devices in such condition that no signal can be received.

3. In a selectivesignaling system, a common line connecting a number of stations with a central station; a signaling device at each station; means located at each station for placing the signaling device in abnormal condition in response to current flowing in one direction; means for restoring said signaling device to normal in response to current flowing in the opposite direction;'and means located at the central station for sendingimpulses of current in either direction.

4. In a party-line telephone system, a central office; a telephone-controller located at each station on a given line; a device for signaling central office located at each station; and means located at central office for operating the telephonecontrollers at the several stations on the line in response to the operation of the signaling device at any station on the same line.

5. In a party-line telephone system, a telephone-controller located at each station; a signaling device at each station; means for operating the several controllers in response to the operation of any signaling device on the same line; and a device for preventing said operating means from taking effect at the station which has originated the call.

6. In a party-line telephone system, normally open telephone and signaling circuits at each station; a manually-operating device at each station for closing the signaling-circuit; controlling devices at each station to prevent the closure of the telephone and signaling circuits by the subscriber; means located at central office and operated by a signaling-current from any station for operating the several controllers on the line over which said signaling-current comes in, the manually-operating device being arranged to comeans temporarily beyond the control of the subscriber at said station; and means located at the central ofiice for operating said device.

8. In a party-line telephone system, a locking-out device at each station to prevent the use of the instrument; means located at each station for operating said locking-out device; means for sending a signal from any station to central; automatic devices for operating the several locking-out devices along a line in response to a signal sent from any station on said line; and means for preventing the eltectual operation of the locking-out device at the station Where the call originated.

9. In a party-line telephone system, acontrolling device at each station adapted to be operated and restored by impulses of current from a source of current located at central office; means for automatically sending an impulse of current from said source to the several stations on a calling-line in response to a signal sent in over said line; means for connecting said calling-line with the line called for; a controller or switch arranged to send impulses of current in one direction to the stations on the called line only, and to send an impulse of current in the opposite direction to the stations of both lines.

10. In a party-line telephone system, acontrolling device for the circuits at each station adapted to be operated by impulses of current from central ot'fice; a source of current; a cord-circuit for connecting two lines; and means for connecting the terminals of said source respectively with the sleeve and tipwires of the calling-plug only, as set forth.

11. In a party-line telephone system, a'controlling device for the circuits at each station adapted to be operated by impulses of current in one direction and to be restored by impulses of currentin the opposite direction; a source of current at central office; means for automatically connecting the terminals of said source with the main wires of a line in response to a signal coming in over said line; a cord-circuit; means for disconnecting said source from the main wires of the calling-line in response to the insertion of the answeringplug; a pole-changing switch for connecting the terminals of said source respectively with the Wires of the cord-circuit; and means operating in response to the movement of the pole-changing switch in one direction for disconnecting the terminals of said source from the cord-wires leading to the answering-plu 12. In a party-line telephone system, acontrolling device for the circuits at each station,

adapted to be operated by impulses of our- ICC rent in one direction and to be restored by impulses of current in the other direction; a

.source of current at central office; a cord-circuit' provided with an answering-plug and a calling-plug; anormally open switch; means for operating said switch to connect the terminals of said source respectively with the sleeve and tip wires of the calling-plug only, for sending operating-impulses over the line to be called; and means for operating 'said switch to connect the terminals of said source respectively with the sleeve and tip wires of both plugs to send a restoring-impulse over both lines.

13. In a party-line telephone system, a signaling circuit at each station normally open; a traveling contact member to close said circuit; a source of current at central office to operate said contact member; and a separate source of current at central office for signalin '14. In a signaling system, a device for placing the instrument at any of the stations on the system in condition to receive signals; means for operating said device bya current flowing over the line in one direction; a second device forplacing the instruments in such condition that no signal can be received; means for operating said second device by a current flowing over the line in the opposite direction; a source of current; and means whereby said source of current can be connected with the line to send current in either direction.

15. In a telephone signaling system, a signal-controlling device at each instrument; an operating device therefor; a restoring device therefor, said operating and restoring devices being controlled respectively by cooperating magnetic members; and means for reversing the polarity of one magnetic member without reversing that of the other, whereby either of said devices may be operated at will.

16. In a telephone signaling system, a signal-controlling device at each station; an operating device therefor; a restoring device therefor, said operating and restoring devices being controlled respectively by electromagnets and their armatures, the said electromagnets being connected in series and provided respectively with polarized and nonpolarized armatures; means for energizing said electromagnets by current flowing in either direction; and means for short-circuiting the electromagnet having the non-polarized armature in response to the attraction of the polarized armature, as set forth.

17. In a telephone signaling system, a signal-controlling device at each station; an operating device therefor consisting of an electromagnet and its armature; a restoring device consisting of a second electromagnet and its armature, one of said armatures being polarized and the other non-polarized; means for reversing the polarity of the electromagnet having the polarized armature; and means operating in response to the attraction of said polarized armature for preventing the electromagnet having the non-polarized armature from being energized.

18. In a telephone signaling system, a linecircuit common to a number of stations connected with a central office; a signalingcircuit bridged across the line at each station; a signal-controlling circuit also bridged across the line at each station; a signal-controlling device located in each signal-controlling circuit; means for operating said signalcontrolling device by current flowing in one direction; means for restoring said signalcontrolling device by current flowing in the opposite direction; a source of current for operating and restoring said signal-controlling devices; and a pole-changing switch for connecting either terminal of said source to either terminal of the main line, as set forth. 19. In a telephone signaling system, the combination with a plurality of signaling devices each of which is normally incapable of being operated from the central office; of a controller for each signaling device to place said device in condition to be operated, all of said controllers being bridged across the line and adapted to be operated by the same agency, but so arranged that when onesignaling device is placed in condition to operate, the

others cannot be operated; means for operat-' ing said controllers by current flowing in one direction over the line; means for restoring said controllers to normal condition by current flowing in the opposite direction over the line; a sourceof current for operating said controllers; and means for changing the direction of current over the line from said source, as set forth.

20. In a telephone signaling system, the combination with a plurality of signaling devices on a single line; ofa controller for each signaling device, the normal condition of the several controllers being such as to prevent a signal from being sent from or received at any instrument; means normally under the control of the subscriber at each instrument for placing said instrument in condition to send in asignal; a locking device for said means beyond the control of the subscriber; means for operating all of said controllers by current sent in one direction over the line from central office, the controllers being so arranged that only one instrument can be placed by its controller in condition to receive a signal at any one time, and said central oflice operating means also operating the several lockin g devices; and means for restoring all the controllers to normal condition by current sent in the opposite direction over the line, as set forth.

21. In a telephone system for party-lines, a signaldevice and controller therefor at each station, the normal condition of which controller is such as to prevent a signal from being received at said station, and a telephone controller at each station; the normal positions of said controllers at any one station differing from the normal positions thereof in any other; and means located at the central office, independent of the source offenergy which operates the signals, for operatin g both controllers at every station, substantially as described.

22. In a telephone signaling system for party-lines, a signal-controller, the normal condition of which is such that no signal can be received, combined with means under control of the subscriber whereby a signal may be sent to central oflice, whereby central office may be signaled without producing signals at other stations on the line; a source of current at central office for operating said controller to place the station where it is located in condition to receive a signal; and an independent source of current for signaling, as set forth.

23.- In a telephone system, the combination with a number of signaling devices on a single line; of a circuit-controller for the signalingcircuit at each signaling device; means for placing one only of said circuit-controllers in condition to render its signaling-circuitoperative, said means operating in response to a predetermined number of impulses of current flowing in one direction; means for placin g all of said controllers in condition to render their respective signaling-circuits inoperative, said means operating in response to a single impulse of current in the opposite direction; an independent source of current for operating said controllers; and means for reversing the direction of current from said source when it is connected with the line, as set forth.

24. In a telephone system, the combination witha number of signaling devices on a single line; of means for producing impulses of current in either direction on the line; a circuitcontroller at each signaling device; means for placing one only of said circuit-controllers in condition to render its signaling-circuit operative, said means operating in response to a predetermined number of impulses of current flowing in one direction; means for placing all of said controllers in condition to render their respective signaling-circuits inoperative, said means operating in response to an impulse of current in the opposite direction; and a manually-operative device at each station for rendering the signaling-circuit at said station operative preparatory to sending in a call, as set forth.

25. In a telephone. signaling system, the combination with a number of signaling instruments on a single line; of means located at central office 'for producing impulses of current in either direction; a circuit-controller for closing the signaling-circuit at each instrument; means whereby each circuit-controller is adapted to close the circuit in response to a certain number of impulses of current in one direction from the central office diflering from the number required to cause a circuit to be closed by any other circuit-controller a telephone-controller at each station; means for operating said telephone-controller in response to theoperation of the signalcontroller; and a device for restoringall of said controllers to normal condition in'respouse to an impulse of current sent in the combination with a source of current where- V by impulses can be sent in either direction over the signal-controlling-device circuit; of

a circuit-controller for the signaling-circuit at each station on one line; means for movinga movable member or contact of the circuitcontroller at each instrument a predetermined distance in response to an impulse of current from the central office, the contact members being so arranged that a certain number of impulses of current will close the circuit at one instrument but not at any other; a controller for the telephone-circuit at each station, said controller coacting with each signal-circuit controller to prevent closure of the telephonecircuit at all stations except the one in which the signaling circuit is closed; and means for restoring the controllers at every station to normal condition in response to an impulse of current in the opposite direction, as set forth.

27. In a telephone signaling system, the combination with an electromagnet and its armature at each station; of a source of current at central oflice for energizing said electromagnet a circuit-controller adapted to be too operated by the movement of said armature;

a spring for restoring said circuit-controller to normal; aretaining-pawl cooperating with the circuit-controller to resist the action of said spring; an electromagnet and armature to operate said pawl, said armature being polarized; and means for reversing the direction of the current from said source atcentral office, as set forth.

28. In a telephone signaling system, a normally open signaling-circuit at the subscribers station; a circuit-closer adapted by a predetermined number of movements in one direction to close said signaling-circuit; said circuit-closer being mounted on a rotatable shaft provided with a ratchet-wheel; an op crating-pawl cooperating with said ratchetwheel; an electromagnet the armature of which is connected with said pawl; means wherebysaid arm ature is caused to effectively operate said pawl when said electromagnet is energized by current in one direction only; a

retaining-pawl; a second electromagnet the armature of which is connected with said retaining-pawl means whereby said second armature is caused to efiectively operate said pawl when said second electromagnet is energized by current in the other direction only; and means located at the central office for energizing said electromagnets by current in either direction.

29. In a telephone signaling system, a signaling-circuit at each station which must be completed before a signal can be sent from or received at said station; a local operating device under the control of the subscriber at each station for completing said signalingcircuit; an electromagnetic system also adapted to complete said circuit when energized by current fiowingin one direction; and to open said circuit when energized by current flowing in the opposite direction; a source of current for energizing said electromagnetic system; and means for sendingimpulses of current in either direction from said source, as set forth.

30. In a telephone signaling system, a signaling-circuit at each instrument which must be completed before a signal can be sent from or received at said instrument; a local'operating device at each instrument for completing said signaling circuit; an electromagnetic system also adapted to complete said circuit when energized bycurrent flowing in one direction, and to open said circuit when energized by current flowing in the opposite direction; a source of current for energizing said electromagnetic system; means for'sending impulses of current in. either direction from said source; and means for preventing the operation of the local operating device at any instrument, said means being operated by the said electromagnetic system, as set forth.

31. In a telephone instrument, the combination with the gravity-hook; of a rotatable locking-disk, the periphery of which is so situated with relation to said hook as to prevent the same'from being lifted; a notch in said disk; and means located at the instrument and adapted to be operated from the central office for causing said disk to rotate until said notch is in line with the said gravity-hook.

In a'telephon'e instrument, the combinationwit'h the gravity-hook; of a rota-table locking-disk, the periphary of which is so situated with relation to said hook as to prevent the same from being lifted; a notch in said disk; means located at the instrument and adapted to be operated from the central office for causing said disk to rotate until said notch is in line with the said gravityhook; and a restoring device for restoring said disk to its normal position.

In a telephone signaling system, the combination with the gravity-hook of each instrument on a single line; of a locking-disk cooperating with said gravity-hook and arranged to lock the same except when said disk is in a predetermined position; and means located at each instrument and adapted to be operated from the central oflice for operating all of said disks in unison, the disks being so arranged that only one at a time can be placed in unlocking position by said operating means, as set forth.

34:. In a telephone signaling system, the combination with the gravity-hook of each instrument on a single line; of a locking-disk cooperating with said gravity-hook and ar& ranged to lock the same except when said disk is in one or. more predetermined positions; means located at the central ofiiee for operating all of said disks in unison, the disks being so arranged that only one at a time can be placed in unlocking position by said operating means; and means also located at each instrument and adapted to be operated from the central office for restoring all of said disks to normal position, as set forth.

35. In a telephone systemflhe combination with the gravity-hook; of a locking-disk cooperating with said gravity-hook at each station on the line and arranged to lock the said gravity-hook except whens-aid disk is ina predetermined position; a normally open signaling-circuit; a circuit-closer carried by said disk and adapted to close said circuit only when said notch is in said predetermined position; and means located ateach instrument and adapted to be operated from the central office for operating all of said disks in unison, the disks being so arranged that only one at a time can be placed in unlocking' position.

'36. In a telephone system, the combination with the gravity-hook; of a locking-disk cooperating with said gravity-hook at each station onthe line and arranged to lock thesaid gravity-hook except when said disk is in a predetermined position; a normally open sigonly when said notch is in said predetermined position; means located at each'instrument and adapted to be operated from the central office for operating all of said disks in unison, the disks being so arranged that only one at a time can be placed in unlocking position; and means also located at each instrument and adapted to be operated from central office for restoring all of said disks.

37. In atwo-conductor telephone system, a normally open telephone-circuit and a normally open signaling-circuit at each instrument; means normally under control of the subscriber for closing both of said circuits; and a controller-circuit bridged across the line at the subscribersstation and a controlling device in said circuit adapted to be .operated from central office for placing said subscribers-circuit-closing means beyond the control of the subscriber.

38. In a telephone system, a normally open telephone-circuit at the subscribers station; and a controlling-circuit bridged across the line at said station and a controlling device in said circuit adapted to be operated from central office for preventing the closure of said telephone-circuit.

39. In a signaling system, a central office and substation; a normally open signalingcircuit at said substation; a device at said substation adapted when in normal condition to close said signaling-circuit; and means located in a circuit bridged across the line at circuit at each station; a circuit-controller located at each instrument and means for operating said controller located at the central office, the said circuit-controller when in normal position closing a switch in the signalsending circuit and leaving the signal-receiving circuit open; and a second normally open switch in the signal-sending circuit under control of the subscriber.

41. In a telephone system for party-lines, a normally open telephone-circuit at each station; means normally under the control of the subscriber for closing said circuit; a device located at each station and adapted to be operated from central office for placing said means beyond the control of the subscriber; a visual indicator cooperating with said device, and means located at each station and adapted to be operated from central office for restoring the telephone-circuit at each station to normal condition, as set forth.

42. In a telephone system for party-lines, a signaling device at each station; a visual busy indicator at each station; and means located at the central oflice and operating in response to the operation of the signaling device for actuating the indicators at the other stations.

43. In a signaling system, a line-circuit; a central station provided with a source of electrical energy; a plurality of signaling-circuits in multiple with said line-circuit; a controller for each of said signaling -circuits; and an electromagnet to operate each of said controllers, the several electromagnets being connected in a multiple circuit supplied from said source of electrical energy.

44. In asignaling system, a line containing a plurality of stations; a signaling device at each station; an electrically -operated controller for each signaling device; a circuit for each controller bridged across the main conductors of the line; a central station; and a source of currentat said central station to supply said circuit, as set forth.

45. In asignaling system forparty-line telephones, the combination with the line conductors; of a signaling device at each station bridged across the line; a controller for each signaling device; and an independent circuit for each controller, said circuits being connected in multiple; and a source of current at central office for supplying said circuits.

46. In a party-line telephone system, a signaling-circuit and a telephone-circuit at each station; a controlling device for each of said circuits; and a controlling-device circuit atv each station independent of the signaling-circuit and the telephone-circuit, each of the said three circuits being bridged across the line.

47. In a signaling system, a signal-controlling circuit; a central station provided with a source of electrical energy and means for connecting either terminal of said source with either terminal of said circuit; a plurality of signaling-circuits in multiple with said signal-controlling circuit; an electromagnetic system for each signaling-circuit,the said electromagnetic systems being connected in multiple with said signal-controlling circuit; armatures included in each of said electromagnetic systems; and means for operating the controllers by the movements of said armatures, the setting of said controllers depending upon the action of said armatures in response to impulses of current flowing in one direction from said source, and the restoring of said controllers depending upon the movements of said armatures in response to current flowing in the opposite direction from said source.

48. In a party-line telephone system, the combination with a telephone-circuit and a signaling-circuit each bridged across the line at each station; of controlling devices for said circuits; an electromagnetic system to oper ate the controlling device at each station, said electromagnetic systems being included in a multiple circuit adapted to receive current from central office and means located at each station for breaking the telephone-circuit and closing a special circuit through said electromagnetic system and that part of the signaling-circuit which includes the bell-magnet coils, substantially as and for the purpose described.

49. In a party-line telephone system, the combination with a telephone-circuit bridged across the line at each station and adapted to be closed by the gravity-hook when the receiver is taken down, and a signaling-circuit also bridged across the line at each station; of means for controlling said circuits consisting in electromagnetic systems at the several stations, said electromagnetic systems being included in a multiple circuit supplied with current from central oftice under control of ICO the operator at central; a special normally FRANK E. MAYBERRY.

, WVitnesses:

GEORGE H. PIERCE, HENRY J LIVERMORE. 

